1. Field of the Invention
The invention relates to a health-promoting composition, and more particularly to a health promoting composition comprising selenium-rich yeast and yeast beta-glucan.
2. Description of the Related Art
Although it is toxic in large doses, selenium is an essential micronutrient for animals. Dietary selenium comes from nuts, cereals, meat, fish, and eggs. Brazil nuts are the richest ordinary dietary source (though this is soil-dependent, since the Brazil nut does not require high levels of the element for its own needs). High levels are found in kidney, tuna, crab, and lobster, in that order. In general, however, the content of selenium in human diet is limited and insufficient.
In humans, selenium is a trace element nutrient which functions as cofactor for reduction of antioxidant enzymes such as glutathione peroxidases and certain forms of thioredoxin reductase found in animals and some plants (this enzyme occurs in all living organisms, but not all forms of it in plants require selenium).
Glutathione peroxidase (GSH-Px) catalyzes certain reactions which remove reactive oxygen species such as peroxide:2GSH+H2O2-GSH-Px→GSSG+2H2O
Selenium also plays a role in the functioning of the thyroid gland by participating as a cofactor for the three known thyroid hormone deiodinases.
Selenium is a component of the unusual amino acids selenocysteine, and selenomethionine, and the amino acid dimer selenocystine, and as such is an important building block of the human body.
Furthermore, selenium is an important component in enzymes affecting metabolism, reproduction, immune system as well as the well being of human beings. It is also known to play a role in preventing cancer, anti-oxidation, and anti-aging.
Since there is insufficient amount of selenium present in normal diet, it is advantageous to supply selenium as food supplement. Inorganic selenium in the form of selenite, or organic selenium, for example, in the form of selenium-rich yeast may be supplied. However, there is a remarkable difference between inorganic selenium and organic selenium in terms of absorption and toxicity, i.e., inorganic selenium is much harder to absorb and has a much higher toxicity. Therefore, a commonly-used source of organic selenium is selenium-enriched yeast.
Using modern biotechnology, selenium-enriched yeast can be made by converting inorganic selenium into organic selenium using brewer's yeast and then separating and refining the organic selenium. 99% or more of all selenium in selenium-enriched yeast is in form of organic selenium, which facilitates faster absorption and low toxicity.
Yeast beta-glucan is a water-insoluble polysaccharide having β-1, 3-D-glucan as main chains and β-1, 6-D-glucan as side chains. It is an important component of yeast cell wall. It can improve immunity, prevent cancer, inhibit bacteria and reinforce resistance against illnesses.
In recent years, there have been many studies on selenium, majority of them focusing on the nutritional mechanism, and a large amount of products have appeared. However, there have been few products made from organic selenium or selenium-rich yeast. Specifically, rather than taking the comprehensive nutritional factor is into account, products have appeared with the sole goal of supplying selenium. In addition, researchers on yeast beta-glucan mainly concentrate on extraction and purification of beta-glucan, and few products, if any, exist.